Well my gmail address worked perfectly last night and this morning, then when I tried to logon this afternoon all my contacts were showing but all as offline - I knew many were online as I have them in AIM too.
Reading a bit more into it I changed my email address back to my .mac one, it accepted it and told me to wait an hour (standard stuff) but I opened Adium, changed the email address back and it worked instantly. Not sure for how long, but for now things are back as they were before we were told to change them!